[highrider407]

i just pulled out the HO and droped in a regular 5.0 with the ecm for that motor, and having major problems getting it to run right. so i want cross check everything to see where i went wrong.

i left all of the emission/smog stuff disconnected, because i don't need it and it takes up to much room. could having all of that stuff not hooked up be causing the engine to run as follows;

8 out of 10 times i start it, i have to prime the throttle body with starting fluid...
rough idle, and likes to stall
half the time she feels like shes misfiring.

any ideals ?????

the timing is dead on
the plugs are good
injectors all register 15.9 ohmz, except for two 14.2 out of the 5.0. the 15.9 are out of the HO 5.0 ( the HO ran fine with these injectors )

who can tell me what is wrong????????????????????????
can supply any photos needed...

[Traidmarx]

you did make sure you changed how the plugs were run since the firing order is different??

[highrider407]

yeah, their set at 15426378 now...

[highrider407]

new firing order is why i switched the ecm's

[1slo5.0]

Maybe that Lincoln engine has some mechanical issues. What computer did you use? We went over this in the last thread, change the cam. Why did you choose a Lincoln engine? You can find Mustang 5 liters for a dime a dozen. It sure would have made things alot easier.

[Racinjason81]

i could have sworn non ho engines used 16 lb white injectors and ho used orange 19lbers

[highrider407]

Your right, it would have made things alot easier, but the Lincoln motor was given to me by my brother, it ran good and strong for being stock. With 60,000 miles on it. I plan to rebuild the HO as I have the money for it this summer. But I need a good running motor in it for this summer. And this motor would be good for a joy rider.

As far as what computer I used, I bought a new one that's for an 88 Lincoln town car. It’s basically the same ECM as the mustang except less fuel and different firing order. Although I now believe that the ECM does not have a preprogrammed setting for a specific firing order.
the HO's oil pump went out before I bought the car and did too much damage to the engine, but it still ran enough to move it around when I needed to, then it just quit run unless, I prime it first. Sound familiar??? At the same time that I had to start priming it to start, the fuel pump would stay on constant, at the time I figured that the relay went bad.
Today when I switched out the ECM, the pump started working the way it is supposed to. So I know that the mustang ECM was junk.
The last thread was in regards to the ECM, no one knew the answer for sure... no,.. There’s something else that I am over looking, this is my first mustang, otherwise I would know the answer to my question.

I’m still looking for someone who knows there stuff... no suggestions???

[highrider407]

they do
but that won't make the fuel rail lock up or stop it from running, it is something that i will have to take care of later though

[highrider407]

15.9 ohmz are the HO's
14.2 ohmz are the non-HO's

[highrider407]

i swithed the injectors to those that were originally in the lincoln moter and with those i'm getting too much air. i think i'm just going to get some new 19 lbs injectors.

[ryans88gt]

Sounds like it will never run again the way things are headed.

Did you swap out the wiring harness as well? You realize the pin out is different for these two motors right?

[fordtruckin89]

so the motor ran before it was harvested from the lincoln?

[fastford3388]

so two of the injectors are from the HO and the other six are from the lincoln motor?? i think you need to get matching injectors. and the lincolns i'm almost positive are sixteen pounders. that may be what you need to get because thats what the ecu wants

[highrider407]

Originally Posted by ryans88gt Sounds like it will never run again the way things are headed. Did you swap out the wiring harness as well? You realize the pin out is different for these two motors right?

yeah, went through the pin order for the ecm to numbered injector, all was good, decided to rebuild the HO though so i put a new ecm for the HO back in it. and the lincoln motor runs better on that ecm.( stronger )she'll run again, the question is, will it take day's, or months, and how much money?

for the record, 88lincoln / 87 mustang per all-data-pro are pinned the same. had me shock, but its the same.

Originally Posted by fastford3388 so two of the injectors are from the HO and the other six are from the lincoln motor?? i think you need to get matching injectors. and the lincolns i'm almost positive are sixteen pounders. that may be what you need to get because thats what the ecu wants

non-HO are 16 lbs 14.2 ohms and HO is 19lbs 15.9 ohms.
the lincoln ecm would run the 19lbs injectors without a problem, but the 16 lbs one are not enough for the HO's ecm.

[highrider407]

yeah, the motor ran fine in the lincoln.
what ever fuel problem i'm having started before i pulled the HO out though, so it's not the ecm (new ). it not the injectors/wiring. it has good pressure at the rail, but i'll put a new filter and probly pump and sending unit in, and see if there's a change.
i've been through everything else.

symtoms are, have to prime to start and has very rough idle 85 percent of ther time. the other 15 it will idle and not stall.
what can stop the injectors from priming the cylinders and not put enough feul through when it idle's ????? let the discussion begin...

[1slo5.0]

Originally Posted by highrider407 i swithed the injectors to those that were originally in the lincoln moter and with those i'm getting too much air. i think i'm just going to get some new 19 lbs injectors.

Getting too much air? Why, are the injectors not spraying? 16lb injectors are plenty for what you have.

[snoel123]

Things that cause you to lose "prime" and by prime I assume you mean you have to cylcle the key several times to so the engine does not require an extended cranking period to start. This is called fuel system leakdown. Excessive leakdown can be caused be several things. Defective checkball integral to fuel pump (on stock in tank fuel pumps), leaking injectors or a leaking fuel pressure regulator. Pull the vacuum line to the fuel pressure regulator to inspect for fuel. If there is fuel in the line it is the regulator. A relative injector flow test can be performed if an injector is suspected. You can monitor fuel rail pressure with a gauge and plug off the return line to eliminate the regulator as a problem. If you can identify a suspect cylinder suspect injectors. to do this simply unplug injectors while the engine is running. whichever one causes the least amount of change relative to the other is the suspect cylinder. Then simply perform a compression test to rule out base engine concerns. The fact that it is an intermittent concern it is highly unlikely an engine mechanical concern. Check fuel pressure. The fact that it runs better with 19s may be because of low rail pressure. Higher flow rate injectors would help mask this.

[Stangzilla]

Originally Posted by snoel123 Things that cause you to lose "prime" and by prime I assume you mean you have to cylcle the key several times to so the engine does not require an extended cranking period to start. This is called fuel system leakdown. Excessive leakdown can be caused be several things. Defective checkball integral to fuel pump (on stock in tank fuel pumps), leaking injectors or a leaking fuel pressure regulator. Pull the vacuum line to the fuel pressure regulator to inspect for fuel. If there is fuel in the line it is the regulator. A relative injector flow test can be performed if an injector is suspected. You can monitor fuel rail pressure with a gauge and plug off the return line to eliminate the regulator as a problem. If you can identify a suspect cylinder suspect injectors. to do this simply unplug injectors while the engine is running. whichever one causes the least amount of change relative to the other is the suspect cylinder. Then simply perform a compression test to rule out base engine concerns. The fact that it is an intermittent concern it is highly unlikely an engine mechanical concern. Check fuel pressure. The fact that it runs better with 19s may be because of low rail pressure. Higher flow rate injectors would help mask this.

I just want to clarify something.. I thought when u cycle the key all that happens is the fuel system pressurizes. Then when you crank the engine the computer is in its "start" cycle. At that time the injectors spray fuel in the cylinders to start the car. I am thinking thats how it works because if u keep cycling the key in a fuel injected car you will not flood it. So I am thinking what he means by prime is the actual introduction of fuel 2 the cylinders during cranking?

[snoel123]

Yes this is true but the term prime is basically the fuel system getting ready to start. the computer turns on the pump via the relay to "prime" the system. This is done so excessive cranking is not required to start you're engine. If the fuel is not reaching the cylinders this can be caused be low fuel pressure, clogged/seized injectors, faulty wiring to the injectors, bad transistor in the pcm (each cylinder has its own so it is unlikely several cylinders fail at once, or the pcm not recieving a proper signal to pulse the injectors, On the 5.0l HO the signal is actually generated at the distributor for crank/cam position to determine which cylinder injects at which time. Theoretically this signal could be disturbed/weak. It is unlikely though. The best thing to do is first check fuel pressure, then kill cylinders one at a time to see if it is isolated or a general misfire. Diagnose in a straight line ruling out the most likely things first, you will save time and money.

Note: that if excessive cranking is an issue leakdown is the most likely cause and least intrusive to prove. Another cause of intermittent rough idle can be a stuck egr valve.

[snoel123]

another thought and correct me if I am wrong. I remember a 95 mustang came to the shop with kind of the same concerns. Someone had forgot to pull the sto inline jumper to kill the electronic advance. His timing was out nearly 20 degrees. i can't remeber if 87 had a jumper but I am pretty sure they do just a thought. Sorry for misreading the prime thing I just glanced through it to fast.